Via ModelGauge algorithms, the MAX17040 and MAX17041 and MAX17043 and MAX17044 one- and two-cell fuel-gauge ICs estimate a Li+ battery’s state of charge without current sensing. They continuously track relative charge state over a varying charge/discharge usage profile and eliminate several discrete components and the coulomb counter. In 2 mm x 3 mm TDFNs, prices for the MAX17040, MAX17041, MAX17043, and MAX17044, respectively, are $0.89, $0.95, $0.99, and $1.01 each/10,000. MAXIM INTEGRATED PRODUCTS, Sunnyvale, CA. (800) 998-8800.